1. Field of the Invention
The invention relates to an apparatus for the mechanical processing of fish of the Trachurus species for the purpose of obtaining fillets or an intermediate product, e.g. suitable for frying purposes, in the form of a headless, abdominally opened and gutted fish body freed from lateral keeled (shield or buckler) scales, the apparatus comprising a conveyor conveying the decapitated fish in the swimming direction along a guideway; a tool for opening the abdominal cavity, including two circular knives arranged symmetrically to the guideway while forming a gap between them; and, if necessary, filletting tools of known construction.
2. Prior Art
The basic aim in the mechanical processing of fish is to achieve a, as high as possible, degree of utilization with the maximum commercial profit. For this purpose, processing must take place with high precision, so that, in the case of the most economical cutting performance, it is safeguarded that the product to be produced is free from quality-decreasing components. In the case of fish of the Trachurus species, which in the different regions of world waters occur in varying appearances and, among others, are known, for example, as scad, horse mackerel or the like, such components consist of the keeled scales located on the body flanks in the tail area, which scales are inconvenient in the gaining of fillets and other products. Therefore it is attempted to remove these keeled scales in order to permit trouble-free processing. However, difficulties are encountered in removing the keeled scales in that the spindle-shaped tail part must be guided very precisely during such processing, in order to achieve a qualitatively satisfactory and economical separation. The desired result can be ahieved very reliably if, during this processing step, the fish body can be guided in its abdominal cavity while the lower side of its vertebral column is being supported. The prerequisite for this is, in first place, the opening of the abdominal cavity, but it has been found that in the case of fish of the Trachurus species the hard or tough structure present at the end of the abdominal cavity in the region of the anus in the form of a fin ray support (pterygophore) supporting the anal fin effects that in the case of such an abdominal cavity guidance the tail part of the fish to be processed is formed in an upward direction over said hard structure, so that it is not possible to process this region, at least not whilst obtaining the desired quality.
From DE-OS No. 14 54 074 a method for processing fish in the region of the abdominal cavity end is known. The object of this method is to process the abdominal cavity end of so-called gadide-type fish formed as a rearwardly extending pocket in such a way that said area receives a configuration continually approaching the edge of the belly towards the tail end. It is intended to ensure through this that spear-shaped guide elements, or, in general terms, elements engaging in the abdominal cavity, do not get stuck in the area of the end of the latter when conveying the fish in the swimming position.
3. Object of the Invention
The object of the present invention is to suggest an apparatus permitting the processing of the region of the abdominal cavity end, particularly in the case of fish of the Trachurus trachurus species or of fish with a similar abdominal cavity end area structure, without yield loss in such a way that on conveying the same in the swimming position, it is possible to guide them precisely by guide elements engaging in the abdominal cavity.